Magnetic Resonance Image Detail and Noise

Outline

Mind Map

Learning Objectives

Teaching Visuals

Online Module
(Requires Enrollment)

Text Reference

 

Outline and Learning Guide


INTRODUCTION AND OVERVIEW

IMAGE DETAIL

NOISE SOURCES

SIGNAL-TO-NOISE CONSIDERATIONS

Voxel Size

Field Strength

Tissue Characteristics

TR and TE

RF Coils

Receiver Bandwidth

Averaging

MIND MAP and SUMMARY

 

 

Learning Objectives

 
  • Describe the general effect of blurring in a magnetic resonance image.
     
  • Describe the general appearance of visual noise in a magnetic resonance image and it's effect on visibility.
     
  • Describe the relationship between the amount of blurring in a MR image and visibility of anatomical detail and small objects.
     
  • Explain and illustrate how changing the protocol factor and matrix
    size affects MR image detail.
     
  • Explain and illustrate how changing the protocol factor and Field of view (FOV) affects MR image detail
     
  • Explain and illustrate how changing the protocol factor and slice
    thickness affects MR image detail
     
  • Identify the possible sources of RF energy that can produce visual noise in MR images.
     
  • Briefly explain why the patient's body is a significant source of visual noise energy and how it can be controlled.
     
  • Explain why it is desirable to have a strong, or intense, RF signal from the patient's body with respect to the problem of image noise.
     
  • Describe the relationship between voxel size and image noise.
     
  • Explain why adjusting protocol factors that affect voxel size must take into consideration both image detail and image noise.
     
  • Describe the general significance of magnetic field strength with respect to image noise.
     
  • Identify and briefly explain the characteristics of a tissue that would contribute to an increased RF signal intensity.
     
  • Describe and illustrate how changing the protocol factor and TR affects the intensity of RF signals from tissue.
     
  • Describe and illustrate how changing the protocol factor and TE affects the intensity of RF signals from tissue.
     
  • Compare the signal-to-noise characteristics of body, head, and surface RF coils for MR imaging.
     
  • Describe the general advantage and disadvantage of using the body RF coil for MR imaging.
     
  • Describe the general advantage and disadvantage of using surface RF coils for MR imaging.
     
  • Briefly describe how the protocol factor and receiver bandwidth has an effect on the noise in an MR image.
     
  • Briefly describe how averaging is used to reduce image noise.
     
  • Describe the general relationship between the protocol factor, number of signals averaged (NSA), and image quality and image acquisition time.
     

 

Text Reference

Chapter 10

Magnetic Resonance Imaging: Principles, Methods, and Techniques
Medical Physics Publishing,  http://www.medicalphysics.org

 

 

Mind Map